7 Key Points to Avoid Failure When Increasing Power Generation ｜ What to Check Before Considering Costs

Table of Contents

• Basics to avoid failure when increasing power output

• Item 1: Check power output data by time of day and by individual system

• Item 2: Separate weather, solar irradiance conditions, and seasonal differences

• Item 3: Inspect panel surface for soiling and its extent before cleaning

• Item 4: Check for shadows from weeds, trees, and structures

• Item 5: Check for abnormalities in connection points, cables, and strings

• Item 6: Check power conversion equipment, temperature conditions, and ventilation

• Item 7: Prevent recurrence by addressing drainage, terrain, and inspection records

• How to set priorities before spending money

• Summary

Basics to Avoid Failure When Increasing Power Generation

When you want to increase the power output of a solar power system, the first thing you need is not to rush into major renovations or adding equipment. Even if the output is low, not growing as expected, or seems lower than before, the cause is not necessarily a single factor. Dirt on panel surfaces, bird droppings and fallen leaves, shading from weeds or trees, faults at connection points, cable damage, inverter stoppages, output curtailment, temperature increases, poor drainage, and insufficient inspection records — multiple factors can overlap and reduce power generation.

For practitioners searching "how to increase power generation," it's important to interpret the phrase "increase power generation" as getting closer to a state where you don't lose electricity that should be generated. In solar power generation, you cannot increase the solar irradiance at the site. You cannot increase the number of sunny days or change the seasonal solar altitude. However, you can move closer to a state in which the received solar irradiance is converted into electricity with as little waste as possible. In other words, improving power generation is the work of finding generation losses at the site and reducing their causes one by one.

A common mistake when trying to increase power generation is deciding countermeasures based solely on the on-site appearance. Cleaning because the panels are dirty, weeding because the grass has grown, and considering replacement because the equipment looks old—these judgments are necessary in some situations. However, if the main cause of the decline in generation lies elsewhere, performing those tasks will not lead to sufficient improvement. Even if you clean, generation will not easily recover if morning and evening shadows remain, and even if you weed, daytime generation will not increase if short stops of the conversion equipment continue.

Before spending money, you should look at when, where, and how the power output is falling. Is it only low in the morning, is the midday peak not reaching its usual level, does it drop only in the evening, does it become unstable after rain, is only certain equipment underperforming, or is the entire plant underperforming? The possible causes to suspect differ depending on these. If you proceed to countermeasures without making this distinction, you may spend time and effort on tasks that have little impact on power output.

To increase power generation, it is important to carry out data checks, on-site inspections, cause identification, countermeasures, effect verification, and record updates as a single continuous process. Performing cleaning or repairs as one-off actions alone makes the same problems more likely to recur. Solar power plants are outdoor facilities, and their condition changes with the seasons, weather, surrounding environment, and equipment aging. That is why, before spending money, organizing the items to check and prioritizing improvements starting with locations that have the largest generation losses is the basic approach to improving power generation without failure.

Item 1: Check power generation data by time period and at the equipment level

Before trying to increase power generation, the first thing to look at is the generation data. If you only look at monthly or annual generation figures, you cannot tell when, where, or how generation losses are occurring. Similarly, even when overall generation is low, the likely causes change significantly depending on whether it is low only in the morning, the midday peak fails to develop, it drops only in the evening, or there are sudden dips during the day. Before spending money, it is important to first check the shape of the generation curve.

If power generation is low in the morning, shadows from east-side trees, slope faces, surrounding structures, or adjacent equipment may be involved. If it is low in the evening, check for shadows on the west side and the influence of surrounding terrain. If the midday peak does not develop, candidates include dirt on the panel surfaces, temperature rise, limitations of conversion equipment, output curtailment, or equipment shutdown. If the generation curve suddenly drops even on sunny days, it is necessary to cross-check shutdown histories and alarm histories with the timestamps.

It is also essential to compare at the equipment level. If you only look at the power output of the entire plant, some anomalies can be masked by the average. Even if it doesn't appear to be a major issue overall, there can be cases where only certain rows, certain strings, or the areas connected to specific conversion equipment have lower power output. If these localized declines are overlooked, generation losses will continue over a long period.

When making comparisons, it is important to look at installations under the same conditions. If you simply compare installations that differ in orientation, tilt, number of panels, shading conditions, or connection configuration, you may mistakenly interpret normal differences as abnormalities. If a specific area is consistently lower compared with adjacent rows or installations with the same orientation, suspect localized soiling, partial shading, poor connections, cable damage, or a fault in the power conversion equipment.

Pay attention to how power generation declines. If it falls suddenly, possible causes include equipment shutdowns, wiring breaks, poor connections, or the appearance of shading or other obstructions. If it decreases gradually, it may be related to the accumulation of dirt, the growth of weeds or trees, deterioration of on-site conditions due to poor drainage, or age-related changes in equipment and components. The locations to inspect and the priorities for countermeasures differ between sudden drops and gradual declines.

Examining power generation data in detail is the most important basis for decision-making before incurring costs. If you can identify which equipment is declining, during which time periods, and by how much, you can narrow down the targets for on-site verification. Rather than wandering aimlessly around a large power plant, focusing on the areas where generation declines are occurring makes it easier to reduce unnecessary inspections and countermeasures.

Item 2: Separate weather, solar radiation conditions, and seasonal differences

When you feel that power output is low, before suspecting equipment malfunction, check the weather, solar irradiance conditions, and seasonal variations. Solar power generation is highly dependent on the amount of sunlight, so during periods with frequent clouds or rain, output will drop even if there is no equipment problem. If you compare only the monthly output with the same month in the previous year or with the previous month and immediately conclude there is an equipment fault, you may find that weather differences were actually the main cause.

On the other hand, we must avoid missing real abnormalities by blaming the weather. If the entire plant is declining uniformly in line with local weather, the effect of solar irradiance conditions is likely large. However, if only part of the plant is underperforming while other equipment at the same plant is operating normally, or if there is a clear difference compared with equipment under the same conditions, weather alone cannot explain it. In such cases, it is necessary to check for on-site causes such as soiling, shading, poor connections, equipment shutdowns, or output curtailment.

To distinguish between causes due to weather and those on the equipment side, it is effective to compare sunny days with other sunny days or days with similar weather. Cloudy or rainy days have large fluctuations in power generation, making the characteristics of anomalies harder to see. If you select and check the generation curves for sunny days, it becomes easier to find the effects of shadows that fall at the same time every day, string-level anomalies where only specific equipment shows lower output, and equipment stoppages that cause drops only for certain periods.

Seasonal differences are also an important factor in decision-making. In winter, the sun’s elevation is lower, and shadows from nearby trees and terrain tend to extend farther. In summer, although solar radiation is stronger, panel and equipment temperatures rise, which can make output harder to increase. During periods of heavy rainfall, monthly power generation tends to be lower, and after strong winds or heavy rain it is necessary to pay attention to fallen leaves, sediment, deposits, poor drainage, and the condition around cables.

Distinguishing weather-related factors before spending money is important to avoid excessive corrective measures. If weather is the main cause, cleaning or repairs will not significantly improve power output. Conversely, if a specific area remains underperforming even on sunny days, it is highly likely that there is room for improvement on site. Separating natural variability from generation losses that can be remedied on site is fundamental to avoiding failure when trying to increase power output.

Item 3: Inspect the panel surface for dirt and the extent before cleaning

Contamination and deposits on the panel surface are a common cause of reduced power output. Because solar panels generate electricity by receiving sunlight at their surface, accumulated dirt reduces the light reaching the cells. The way panels become soiled varies with site conditions, such as soil dust, pollen, yellow sand, bird droppings, fallen leaves, sap, dust from nearby construction, road-borne dust, and salt-containing grime that tends to adhere in coastal areas. Even light dirt can affect power output if it spreads over a wide area, and localized deposits can act as a strong shadow even over a small area.

However, just because something appears dirty does not necessarily mean cleaning should be the top priority. If the main causes of reduced power output are shading or equipment shutdowns, cleaning alone will not lead to sufficient improvement. Before cleaning, confirm whether the equipment with low power output corresponds to the areas where dirt is most noticeable. If, compared with equipment under the same conditions, only a particular row shows lower output and that row has concentrated lower-edge soiling or bird droppings, then the priority for cleaning should be high.

Particular attention should be paid to streaks of dirt that remain at the lower edge of the panels and around the frames. It is often assumed that rain will naturally wash them away, but in reality rainwater flow can collect the dirt at the lower edge and leave it there. Panels with a shallow tilt do not drain well, making dirt prone to accumulate. Even dirt that is not noticeable from a distance can affect power generation if it covers part of the solar cells. During on-site inspections, it is necessary to carefully check not only the overall color of the panels but also the lower edges, corners, and areas around the frames.

Localized deposits such as bird droppings and fallen leaves should not be underestimated. Unlike dirt that spreads thinly across the entire surface, these cover specific spots densely and hinder power generation by creating partial shading. Rows near trees, areas around structures where birds are likely to perch, downwind rows, and locations near unpaved paths are more prone to soiling and deposits. These places should be prioritized for inspection while cross-referencing power generation data.

When performing cleaning, it is essential that the equipment is not damaged. You should avoid vigorously scrubbing with hard tools, carrying out sudden work during times when the panels are hot, or skipping electrical safety checks. Also, recording before-and-after photos, the cleaning area, the work date, weather conditions, and changes in power output makes it easier to verify the effectiveness of the cleaning. Before spending money, it is important to check not only for the presence of dirt but also the relationship between the extent of soiling and the decline in power generation.

Item 4: Check for shadows from weeds, trees, and structures

To avoid mistakes when trying to increase power generation, checking for shadows is essential. Because solar panels generate electricity from sunlight, even a shadow on part of a panel can reduce output. Sources of shadows include weeds, trees, fences, utility poles, nearby buildings, mounting structures, adjacent rows of panels, monitoring equipment, and more. Shadows move depending on the time of day and season, so just because you didn't see a shadow during an inspection doesn't mean there isn't a problem.

Weeds are a common cause of on-site power generation losses. Even if there are no problems in winter or immediately after installation, they can grow rapidly from spring through summer and cast shadows on the lower edges of panels and the front rows. Even if the plants are not touching the panels, the low sun angles in the morning and evening produce long shadows. Furthermore, when weeds become overgrown, airflow worsens, inspection walkways are blocked, and it becomes difficult to check around equipment. Because they affect not only power output but also maintainability and safety, weed management is fundamental to improving generation.

Shadows from trees are a factor that can become problematic during long-term operation. Trees that had little effect at the time of installation can grow over several years and reduce power generation. Trees located to the south, east, and west in particular cast shadows on solar panels depending on the time of day. At power plants near forests or slopes, the height of the terrain combined with the height of trees can create long shadows in winter. If output is low only during winter, or if there is a large drop in the mornings and evenings, it is necessary to check both trees and terrain together.

When checking for shadows, it is important to align the inspection with the time periods when power output data shows a drop. If output is low in the morning, check the on-site conditions in the morning; if it is low in the evening, look for evening shadows. Even if there is no problem at noon, there may be significant shadows in the morning or evening. Also, even if there is no problem in summer, shadows can extend during seasons when the solar altitude is lower. When you find a shadow, record the time it occurs, the source of the shadow, the equipment affected by the shadow, and photographs.

Care must also be taken regarding shadows cast by nearby structures and additional equipment. Adding new equipment within the power plant, or installing fences, signs, or monitoring poles, can cast shadows at certain times of day. Before spending money on countermeasures, it is necessary to determine whether the decline in power output is due to permanent shading, temporary shading from weeds, or seasonal shading from trees. Depending on the cause of the shading, the measures to take—weed removal, pruning, repositioning, or adjusting inspection timing—will differ.

Item 5: Suspect abnormalities in connection points, cables, and strings

The causes of low power generation are not limited to the panel surface or shading. Even if solar panels are receiving sunlight normally, faults in connections, cables, or strings can prevent the generated electricity from being fully extracted. String-level differences in power output, loose terminals, poor electrical contact, damage to cable insulation, moisture ingress, animal damage, damage during mowing operations, and deterioration due to aging are important causes of reduced power generation.

When checking for abnormalities at the string level, compare strings under the same conditions. If you simply compare units with different numbers of panels, orientation, tilt, shading conditions, or connection configurations, you may mistakenly judge normal differences as abnormalities. Check whether any are consistently lower compared with adjacent rows or equipment with the same orientation. If only a specific string is lower, possible causes include soiling, partial shading, poor connections, cable damage, or equipment-side problems.

You should suspect faults in connectors or cables when only particular equipment has low power output, when anomalies tend to occur after rain, when generation suddenly drops, or when output fluctuates unstably. If a portion is underperforming despite no visible dirt or shading, electrical faults should also be considered. If there is a persistent difference compared with a string under the same conditions, prioritize checking the connectors and cables.

Cable and connection point failures are also related to the surrounding environment. In areas with a lot of weeds, it becomes difficult to inspect the condition of cables. In locations with poor drainage, humidity and standing water can affect the connections. On sites where animals can easily enter, cable damage can also occur. For improving power generation, it is essential not only to carry out repairs but also to check the site conditions that could lead to recurrence.

When checking electrical equipment, safety must be the top priority. Even if you want to increase power generation, on-site personnel should avoid forcibly touching connection points or the inside of equipment to make judgments. Organize which equipment is showing abnormalities, the time of occurrence, changes in power generation, on-site photos, and the surrounding environment, and, if necessary, escalate to a professional inspection. Before incurring costs, clarify where an abnormality is suspected and whether the evidence lies in the power generation data or the on-site conditions.

Item 6: Check conversion equipment, temperature environment, and ventilation

The cause of low power generation is not just the panels and wiring. If the equipment that converts the generated electricity has stopped or its output is being limited, generation will not increase even when solar irradiance is sufficient. To avoid failure when trying to increase generation, it is essential to check the operating status of the conversion equipment, stop history, alarm history, and whether output curtailment is in effect.

When checking stoppage history, confirm which equipment stopped, when it stopped, and for how long. Even short outages can cause large losses if they occur during daytime when generation is high. If stops and recoveries recur during the day, the monthly total may not look significant, but in practice you may be losing generated energy. Whether only particular equipment stops or multiple units stop simultaneously will change which causes you should suspect.

When output curtailment occurs, power generation can level off even on sunny days. If the top of the generation curve looks flat, check the operating information and history. However, a flat curve does not necessarily indicate output curtailment. Similar shapes can be caused by equipment capacity limits, temperature rise, soiling, shading, or measurement anomalies. Do not judge based only on the generation curve; it is important to verify by comparing equipment records with on-site conditions.

Temperature conditions are another point to review. While solar power generation is generally easier with stronger solar irradiance, rising panel temperatures or higher temperatures around equipment can make it harder for output to increase. If generation does not rise as expected on a clear summer day, you need to check the thermal environment as well as the irradiance. Overgrown weeds beneath panels, grass or obstacles around equipment, or dust and deposits that hinder heat dissipation can affect the increase in power generation.

Environmental maintenance around equipment is something that can be easily checked before spending money. By keeping the area around the equipment easy to see, reducing vegetation and debris that obstruct ventilation, and ensuring abnormal indicators and external appearance are easy to inspect, stoppages and abnormalities can be detected sooner. To avoid confusing equipment-side faults with panel-side problems, it is important to cross-check the time of any drop in power generation with the equipment history and isolate the cause based on evidence.

Item 7: Prevent Recurrence through Drainage, Topography, and Inspection Records

Drainage, topography, and inspection records are often overlooked in efforts to increase power generation. Even if you only check the panels and equipment, at sites where the same generation losses recur, the cause may lie in the overall environment of the plant. Areas where water tends to accumulate, where sediment can flow in, access routes prone to becoming muddy, slope failures, erosion around mounting racks, and places where cables are likely to become exposed can lead to dirt accumulation, weed growth, connection failures, and reduced ease of inspection.

Areas where puddles remain after rain are more prone to weed growth. When weeds grow, they create shade, reduce ventilation, and make inspections more difficult. Muddy walkways can slow work and reduce the frequency of cleaning and weeding. Where sediment flows in, it accumulates under panels and around cables, causing dirt and damage. If cleaning and weeding fail to stop the same problems from recurring in the same location, drainage or topography issues should be suspected.

When checking terrain and drainage, on-site inspections after rain, not just during sunny weather, are effective. Identify where water flows in, where it pools, and where it drains away. Recording puddles, sediment deposition, vegetation overgrowth, path subsidence, and changes to slopes will reveal locations prone to recurrence. If poor drainage is left unaddressed, soiling and weed growth will recur, resulting in the same power generation losses occurring repeatedly.

Inspection records are also indispensable for preventing recurrence. If you record the locations of equipment with low power output, rows that are prone to soiling, places where shadows occur, spots where water accumulates, locations of connection failures, repaired areas, and the areas where cleaning or weeding was performed, it will be clear which places need to be checked at the next inspection. If records are insufficient, even if the same problems recur you will not be able to learn their causes and will have to check everything from scratch each time.

As a point to check before spending money, confirming the causes of recurrence is extremely important. Don’t just clean the dirt—check why that spot tends to get dirty. Don’t just mow the grass—look at why grass grows easily in that area. Don’t just repair the connections—check background factors such as moisture, drainage, and cable exposure. Adopting this perspective makes it easier to sustain the effects of power generation improvement for a longer time.

How to Decide Priorities Before Spending Money

To avoid failure when trying to increase power generation, it is important to set priorities before starting countermeasures. Trying to solve all problems at once can increase the workload and lead to measures that would have a large impact on power generation being postponed. First, prioritize confirming equipment that shows a clear decline in power generation data, shadows with long impact durations, recurring soiling or drainage failures, and equipment that experiences frequent stops even for short periods.

When deciding priorities, we consider the impact on power generation, the likelihood of recurrence, ease of inspection, and safety together. If equipment with clearly low power output is overlapped by dirt or shading, cleaning or weeding is given higher priority. If only a specific string is low, it is necessary to check the connection points, cables, and the equipment side. If the same location has problems after rain, we re-examine drainage and topography. Before spending money, it is important to determine which cause has the greatest impact on power generation.

After implementing countermeasures, always check how power generation has changed. After performing cleaning, weeding, repairs, equipment inspections, and drainage checks, record the power generation before and after the work, on-site photos, the scope of the work, and the weather conditions. It is difficult to completely remove the influence of weather, but by comparing sunny days with one another and comparing with facilities under the same conditions, you can identify certain trends. Prioritize measures that showed a large effect for subsequent occasions, and if an effect is difficult to see, suspect other causes.

Also, improving power generation is not something that can be completed with a single intervention. Solar power plants are outdoor facilities, and their condition changes with the seasons, weather, surrounding environment, and the aging of equipment. Even if you clean them, dirt will return; even if you remove weeds, grass will grow back; trees will grow; and equipment and wiring will change over long-term operation. To stably increase power generation, you need a system that continues inspections and record-keeping rather than treating countermeasures as one-offs.

When multiple personnel manage a site, it is also important that they can accurately share the same location. In a large power plant, where similar rows and equipment are lined up, it can be difficult to identify a location from photos alone. If equipment numbers, location information, photos, and work history are recorded together, field personnel, management personnel, inspection personnel, and repair personnel can more easily confirm the same location. If priorities can be shared, decision-making on countermeasures will also be smoother.

Summary

To avoid mistakes when trying to increase power generation, it is important to identify the causes of generation losses in order before spending money, and to address the areas that have the greatest impact on power output first. In solar power generation, you cannot increase the solar irradiance itself on-site. However, you can improve power output by bringing the system closer to a state that converts the received irradiance into electricity without waste. To do this, it is necessary to check, in order, generation data, weather and irradiance conditions, dirt on panel surfaces, shadows from weeds and trees, connections and cables, power conversion equipment, drainage, and inspection records.

When you feel that power generation is low, rather than immediately carrying out cleaning or repairs, it is important to first separate and review the data. Determine when the output is low, which equipment is underperforming, and whether there is a difference compared with equipment under the same conditions. By then inspecting the site, you can identify where cleaning is needed, the areas that require weeding, the connection points that should be inspected, the equipment that needs to be checked, and the drainage and access routes that should be reconsidered. For improving power generation, it is important to make decisions by linking data with on-site conditions, not by relying on intuition.

Also, measures to increase power generation are not completed by a single operation. Even if you clean, dirt will reaccumulate; even if you remove weeds, grass will grow; trees will grow; and equipment and wiring will change condition over time. By comparing power generation before and after measures, keeping on-site photos and work records, and using them for the next inspection, the accuracy of improvements can be increased. To consistently increase power generation, it is essential not only to eliminate the causes but also to create a site environment and management system in which the same causes are less likely to occur.

In particularly large power plants, a system for accurately sharing problem locations is crucial. If dirty-prone rows, areas where shadows occur, places where water accumulates, abnormal strings, repair sites, cleaning extents, and inspection photos are recorded with location information, stakeholders can more easily confirm the same locations. By combining power generation data with on-site location information, it becomes easier to explain priorities for cleaning, weeding, and repairs, and to streamline recurrence checks in subsequent inspections.

If you want to continuously manage the seven items for avoiding failures when increasing power generation based on field data, using LRTK is also effective. As an iPhone-mounted GNSS high-precision positioning device, LRTK is useful for recording inspection locations within a solar power plant, places prone to dirt, areas where shadows occur, sites of poor drainage, abnormal equipment, repair locations, cleaning areas, and on-site photos together with high-precision location information. By documenting the points to check with location information before spending money, it becomes easier to pursue power generation improvements based on field data rather than on intuition.